diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 9406c1e3ae5..48e92d58172 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -1175,7 +1175,7 @@ abstract class CommonObject
 		$this->db->begin();
 
 		$sql = "DELETE FROM ".MAIN_DB_PREFIX."element_contact";
-		$sql .= " WHERE rowid =".$rowid;
+		$sql .= " WHERE rowid = ".((int) $rowid);
 
 		dol_syslog(get_class($this)."::delete_contact", LOG_DEBUG);
 		if ($this->db->query($sql)) {
diff --git a/htdocs/expedition/contact.php b/htdocs/expedition/contact.php
index d1bcab57412..9d5b7c4a8af 100644
--- a/htdocs/expedition/contact.php
+++ b/htdocs/expedition/contact.php
@@ -99,7 +99,7 @@ if ($action == 'addcontact' && $user->rights->expedition->creer) {
 	$result = $objectsrc->swapContactStatus(GETPOST('ligne', 'int'));
 } elseif ($action == 'deletecontact' && $user->rights->expedition->creer) {
 	// Efface un contact
-	$result = $objectsrc->delete_contact(GETPOST("lineid"));
+	$result = $objectsrc->delete_contact(GETPOST("lineid", 'int'));
 
 	if ($result >= 0) {
 		header("Location: ".$_SERVER['PHP_SELF']."?id=".$object->id);
diff --git a/htdocs/projet/contact.php b/htdocs/projet/contact.php
index fe434891fa9..92f4e4e3b15 100644
--- a/htdocs/projet/contact.php
+++ b/htdocs/projet/contact.php
@@ -223,7 +223,7 @@ if ($action == 'swapstatut' && $user->rights->projet->creer) {
 // Delete a contact
 if (($action == 'deleteline' || $action == 'deletecontact') && $user->rights->projet->creer) {
 	$object->fetch($id);
-	$result = $object->delete_contact(GETPOST("lineid"));
+	$result = $object->delete_contact(GETPOST("lineid", 'int'));
 
 	if ($result >= 0) {
 		header("Location: contact.php?id=".$object->id);
diff --git a/htdocs/reception/contact.php b/htdocs/reception/contact.php
index 58e046ec0bb..3caa9a90fea 100644
--- a/htdocs/reception/contact.php
+++ b/htdocs/reception/contact.php
@@ -110,7 +110,7 @@ if ($action == 'addcontact' && $user->rights->reception->creer) {
 	$result = $objectsrc->swapContactStatus(GETPOST('ligne', 'int'));
 } elseif ($action == 'deletecontact' && $user->rights->reception->creer) {
 	// Efface un contact
-	$result = $objectsrc->delete_contact(GETPOST("lineid"));
+	$result = $objectsrc->delete_contact(GETPOST("lineid", 'int'));
 
 	if ($result >= 0) {
 		header("Location: ".$_SERVER['PHP_SELF']."?id=".$object->id);
diff --git a/htdocs/resource/class/dolresource.class.php b/htdocs/resource/class/dolresource.class.php
index 5ab07cdd536..4979a883d9c 100644
--- a/htdocs/resource/class/dolresource.class.php
+++ b/htdocs/resource/class/dolresource.class.php
@@ -410,7 +410,7 @@ class Dolresource extends CommonObject
 		$this->db->begin();
 
 		$sql = "DELETE FROM ".MAIN_DB_PREFIX.$this->table_element;
-		$sql .= " WHERE rowid =".$rowid;
+		$sql .= " WHERE rowid = ".((int) $rowid);
 
 		dol_syslog(get_class($this), LOG_DEBUG);
 		if ($this->db->query($sql)) {